However, the study also showed some promising figures. It indicated that the percentage of active duty military service members who voted jumped from 24 percent in 2006 to 29 percent in 2010, an increase of 21 percent.

One reason for the sharp increase, the study says, is the passage of the Military and Overseas Voter Empowerment Act of 2009, which required electronic ballot delivery, the availability of the ballots 45 days prior to election day, and expediated ballot return for overseas military voters.

Because the military is much more male and much younger than the general voting population, the study adjusts the rate to more closely mimic the demographics of the general population. Adjusted for age and gender, 46 percent of activity duty military service members voted in the 2010 election, up from 43 percent in 2006.

This constrasts sharply with the general population - in 2010, only 45.5 percent of the citizen voting age population cast ballots, down from 47.8 percent in 2006.

Activity duty military were also more likely to be registered to vote. In 2010, 85 percent of active duty military were registered to vote, adjusted for age and gender. This is compared to only 65 percent voter registration in the general population.

The study was commissioned by the Federal Voting Assistance Program, which aims to help service members, their families and citizens living outside the U.S. to vote. The report cost the Department of Defense almost $2.4 million to prepare and analyze.